New Delhi, Sept. 23 -- By Thursday afternoon, investors holding Boeing, Nvidia, or any of the two dozen semiconductor names tied to US export controls will know which of three numbers moved their stocks. The Trump-Xi summit communique will contain soybean purchase commitments, chip licensing language, and auto and battery localization terms. With the tariff truce expiring in 50 days, those three paragraphs matter more than anything else on the summit agenda.

moves that reflected relief at last weekend's preparatory session in New York rather than conviction about what Washington and Beijing would actually agree. Ed Yardeni, president of Yardeni Research, cut his year-end S&P 500 target from 8,400 to 7,900 last week, a reduction driven le...